Skip to main content ↑ ↓
Topic: Just a bit more power, HP & torque. (Read 1158 times) previous topic - next topic

Just a bit more power, HP & torque.

Sometime ago Barry & Cindy wrote "I would not recommend buying too small and planning to increase HP with Banks.  Buy what you want and stay with it."
Now I know most of you are going to agree with that I do too. When I (just) purchased our 94/U225 with 230HP Cummins B engine & Allison 4 speed 643 I knew it was the entry MH FT build that year. Also I believe it was the lightest one. While maybe I could have purchased a FT around 40K we liked the GV U225 and our purchase price (starting point) was right for us. My intentions with it is to keep it for a long time, hence gradually I am willing to spend some money to bring it to the point that I will like it even more than I do now. Please look at it as if it is a classic car that deserves remodeling & restoration. IMO any older FT is a classic.  So maybe not right away but I plan to do something's to its Engine, transmission and differential to get somewhere around 30-40 or so more HP. While I hope to not decrease the fuel mileage too much. Now so far we have only done a 700 mil trip with it and it was wonderful, thank God so far so good. As I get the advice from almost everyone "Drive it, use it for sometime before spend so much on it" I give the same advice to myself, but I have some long and short term plans for it. A bit more power for it , I hope is within the first year. After I do 3-4 more trips wit it. This will be more true if the MH does not come up with major expenses of its own :(  Most peoples homes are in best shape right before they sell it; the hardwood floors or the kitchen remodel that they talked about somehow happens right before they sell it & folks never enjoy it. I like to be able to do few things to it so while we have it we can enjoy it.
What I am hooping to take your time with this posting is advice, opinion and perhaps some expert technical knowledge that can lead me in to right path in achieving 6-9mph more power when I am entering/merging in to a highway. Now I am hoping to not swap/upgrade engine or spend 10K doing this :-) .. I am reading about Banks Stinger, Propane injection, etc. What do you all know or if you have done anything that truly worked.
I thought about writing and asking this for few days ... sometimes things get lost in translation in today's modern communications (e-mails, txt, blogs)  I hope to not make a fool of myself & when all said and done I may just be happy with it as it is, but I need to know what is possible within reason.
Thank you,
AL

Re: Just a bit more power, HP & torque.

Reply #1 –
There is no such thing as enuf power, being a gear head, I want as much power as the engine is capable of within the manufacturers capabilities and not "Hot rodding" it.
I would go to Cummins and find what your engine is capable of and staying within Cummins blessing.
That is exactly what I did with my ISM450, making it into the ISM500+ all the work was done by Cummins and with their blessings.

The pie in the sky, more power and better fuel mileage is possible, however with the power, you tend to use it, making better time with similar mpg, it is also easy to get worse mileage, it all depends on the right foot. I expect you will have a problem finding a Cummins factory shop that will spend the time & effort to dig deeply into this.
My opinion, leave it alone and enjoy it.
Dave M

Re: Just a bit more power, HP & torque.

Reply #2 –
Keep in mind that when you "turn" up an engine past what it was "born" from the plant you shorten the life expectancy of that engine. But in your case with an mechanical engine I would think about your transmission, too much boost and it may start having problems. Our MH trans are usually rated for the torque that the engine puts out from factory.

I have had a 1997 Dodge diesel mechanical engine that we took back to dealership and they turned up the fuel pump and tweeked timing, we had more pick up and got better fuel mileage. He never would tell me exactly what he did but wow it made a difference.
If you still want to turn up your engine you may search out an older Dodge Cummins mechanic that worked on the older mechanical engines.

Oh and by the way I had a Ford 6.9 diesel that we put a Banks turbo kit on, the kit made the truck "wake up" but after 30K miles we had to replace the head gaskets from leaks.

Re: Just a bit more power, HP & torque.

Reply #3 –
I'm afraid that getting another 6-9 mph over the course of a freeway onramp is going to require a *much* larger increase in output than 30-40 hp in even a "lightweight" U225...11 tons ain't gonna notice 30 HP all that much. i suspect all you'd accomplish is increased engine wear without enough extra punch to make a difference. I testdrove a couple of 5.9 Cummins-equipped coaches before we found our FT. They were both the same size, probably pretty close to equivalent weights, one was stock and the other had bigger injectors, a turned up pump, and a gearvendors overdrive on the transmission. Accelleration was maybe  little bit better in the hotrodded coach, but wihout a side by side drag race it wasn't enough to really tell a difference. The only really noticable difference wias the amount of coal coming out the tailpipe at full throttle. What I'd do, and what I'm researching doing to ours, is check to see if it has an intercooler. If it doesn't, like ours, then there is isome incentive to install one. Denser intake air at lower temps is good for lower EGT and onramp mergeability.

Re: Just a bit more power, HP & torque.

Reply #4 –
While you may be able to gain a little bit more by "tweeking" you likely will not be able to tell much difference. The next step is performance kits and programmers(more $$$). However in general when you start making more HP/torque you also start raising exhaust and coolant temps, and bad things start happening if you are not careful.

If you have the book on the engine that came with the coach it will have a chart indicating at what RPM your engine makes the most torque and horsepower. You can manually use the transmission to keep the engine operating in that range (especally when pulling long grades). The 5.9 and 8.3 engines are usually happier in the 1700-2000 rpm range. A lot of folks roll down the road with these engines turning 14-1500 rpm and no power. The 5.9 cummins is a great engine just about bullet proof within it's limitations.

Re: Just a bit more power, HP & torque.

Reply #5 –
Our FT with Cummins 350-8.3 was fitted out by PO with Banks Stinger and for me it made a large difference in HP as last year there was an electrical 12v problem and the banks was not working. I thought I was pulling another coach behind as the difference was significant. Once fixed it was back to full power. It has done maybe 40k miles since it was added and not one problem on engine. I later did the Resonator upgrade and that has decreased temp' in engine significantly, so all in all I would say it was a good move and HAS increased performance in many ways.
John H

Re: Just a bit more power, HP & torque.

Reply #6 –
To understand exactly how much performance gain you would have for a given HP increase on a 6% grade, go to page 6 and 7 of this document: Understanding Coach /RV Performance

Note on EDIT:  Can't get the link to work-- have mailed Steve and Michelle. Meanwhile, click on the link, then "Forum" in upper left of page, then on "Driving and Operation".  The "Understanding Coach (RV) Performance" Document is the last one on the bottom.

I think you will find that even a 5 MPH increase takes quite a large increase in HP.  And, the document is HP at the rear wheels-- so an even larger increase in engine HP is needed to produce those results.

Then you get into whether the cooling system was OVERengineered enough to accommodate the additional heat load, transmission is rated for the additional HP, etc

Not suggesting you do/don't do it, but be aware of the cost/benefits.

Re: Just a bit more power, HP & torque.

Reply #7 –
Al, Thanks for our quote credit. I think there are many who have 'upgraded' engine with Banks, etc and are very happy and have no problems, so you should have no problems.

On the other hand, we have diesel mechanic friend who speaks Foretravel, that put a Banks kit on his coach. He loved the power, but noticed that Exhaust Gas Temps from the pyrometer much higher than before. They would get so high so quickly on a hill pull that he was concerned about engine damage if he did not keep an eye on the gauge. After a while he found it easier to remove the Banks kit than drive with his eye on pyrometer. He may have been able to reduce the injector pump fuel flow, to reduce power and heat.

If increasing power overloads engine, cooling, bearings, transmission, universal joints, it will not happen quickly, so only time will tell the story.

Anyone contemplating Banks should change muffler first to see if there is a power or MPG increase.

While some have increased MPG, it is really hard to make a dent in the low MPG we all have gotten used to.

Re: Just a bit more power, HP & torque.

Reply #8 –
The surest way to increase performance and fuel economy and increase life expectancy of your equipment is to lose as much weight as practical. If you drive with your tanks as empty as practical, only the cargo you actually use, and no toad, you'll probably find your coach has plenty of power, especially climbing steep grades. You'll probably pass more heavily loaded coaches with more powerful engines while climbing steep hills ...and then of course they'll pass you going down the other side trying to hold all that weight back. This is a free performance upgrade that you'll notice immediately.

Re: Just a bit more power, HP & torque.

Reply #9 –
 Barry, as I mentioned in my note above with the resonator the engine heat dropped quite a bit (around 200 deg I bet) and that compartment is cooler and the bed cold after a drive!! No more nice warm bed to get into on those chilley nights, so right there it tells me something!! The times I have driven up the "Grapevine" and watching the pyrometer while I am passing all those slow trucks, tells me the engine has not become too hot. I also use Amsoil which takes good care of the heat better than regular non-synthetic oil.
John H

Re: Just a bit more power, HP & torque.

Reply #10 –
During our 700 mil trip i noticed time to time oil temperature was coming up to 225 maybe 230 degree. That would happen when I used cruse control on 67-68 mpg for 15-20 min or so ... (outside temp was 95+) and I would back down to 55mph right away, at first I even took exit right away and let it cool down and once went under 200 degree I shut the engine for 10-15 min. We were not pulling anything we had just over half tank fresh water, some in black and gray. Diesel fuel was 3/4 to 1/2, propane was 1/2+ We did not have much of anything under the storage area, most heavy thing was my tool box. Water temperature once went a bit over 200 and when i backed down it went back under 200 degree.
Slowly I am gathering that first think I may tackle is the muffler and see what it brings.
I read about How do exhaust headers work to improve engine performance? ( http://auto.howstuffworks.com/question172.htm )  & The Resonator ( HowStuffWorks "How Mufflers Work" )
I spoke with these guys (father & son) MAC'S PERFORMANCE for Cummins, Duramax, Powerstroke, R.V.'s and Hotrods - Main and I believe they know what they are doing. They were not so much recommending to mess with it much. He said maybe they will move the "fuel" plate a bit and kind of tune it up ... He said he will drive it, listen it and within reason if there is any safe room to increase some performance he will apply his years of Diesel experience and hope he can help it a bit. I am going to have them also fix the "KDP" Killer Dowel Pin.
He said once he plays with the "fuel" plate after that depending on how much black smoke it pushes out, he may do something with the boost actuator (wastagate actuator)
So if to get 6-9 mph requires so much HP, I may just do things to make it cool better & breed better & leave it at that.

I also spoke with Allison Transmissions, Rebuilt Allison Transmissions, Remanufactured Allison  in Arlington, TX (Allison Transmission) He said that the 643 will be able to handle 250+ HP He indicated that lot of folks push it to 275+ and it does just fine .... He also said it is one of the strongest & cheapest Transmissions to rebuild :-) @ 1700 ::)
Thank you for all the input ... this is turning out to be a good discussion and I am sure few more folks be interested in this discussion too ... Keep it coming.

Since we already have propane on board, how about propane injection? from what I can tell it does something but not cost effective, while using 3 gal diesel it ends up also using 1 gal propane so in today's numbers it will be 3x3.70(D)+1x3.00(P) for about 27-33 miles.
Thank you,
AL

Re: Just a bit more power, HP & torque.

Reply #11 –
My U240 with the CAT 3116 seems to have plenty of get up and go even with full water / fuel / propane though I do try to drive with the black and gray tanks near empty.  Even on some of the mountain driving on the trip out west it did ok.  Maybe I just don't have any other MH experience to compare it to.

Re: Just a bit more power, HP & torque.

Reply #12 –
Quote
Note on EDIT:  Can't get the link to work-- have mailed Steve and Michelle.

Link fixed in the OP ... repeated here as well

Understanding Coach /RV Performance

Re: Just a bit more power, HP & torque.

Reply #13 –
Thanks, Steve.

A good document on HP requirements for motorhomes.

Re: Just a bit more power, HP & torque.

Reply #14 –
Very good document. Thank you.
I wish there was a way to add electrical radiator fan and get the 15-20 HP by removing the belt, but I think cooling power by the engine driven fan can not be achieved with electrical fan ... maybe there is such fan out there but I don't know.
I need to find a way to run cooler somehow; bigger radiator or something or a second radiator added in the front as Kent did on his U225.
So far I am entertaining the idea of upgrading its manifold to a 3 piece one & an intake elbow upgrade &  resonator. I may go with ATS performance products.
 

Re: Just a bit more power, HP & torque.

Reply #15 –
Al,

Yes, if you have optimized the OE cooling system and still have heating issues, I would add a front radiator with 3 way valves from dash heater.

But, make sure your cooling system is optimized first.  Start by completely cleaning the front surface of the CAC-- that is what you are looking at when you look inside the fan shroud from the bedroom.  Pay particular attention to the lower perimeter, as that is the area that clogs up quickest.  Unless you have complete maintenance logs and coolant has been changed as it should, it is also quite possible that the radiator needs servicing/replacement.